1. Field of the Invention
The present invention relates to an engine-driven work machine connected to and driven by an engine. The work machine includes a duct member disposed around outer peripheries of the engine and the work machine to define a continuous cooling-air passage between the duct member and the outer peripheries. A cooling fan is disposed in the cooling-air passage to generate cooling air flowing from one end of the cooling-air passage to the other end during operation of the engine. An exhaust muffler of the engine is disposed in the vicinity of the other end of the cooling-air passage, wherein the exhaust muffler is cooled by the cooling air flowing out of the cooling-air passage. The work machine driven by the engine encompasses a generator, an air compressor, a storage pump, and the like.
2. Description of the Related Art
Japanese Patent Application Laid-open No. 2005-30353 discloses an engine-driven work machine or generator.
An engine-driven generator is broadly used as a temporary power source in a construction site and other outdoor places. Therefore, it is often required to minimize the operational noise of the engine-driven generator in consideration of the environmental surroundings.
In the engine-driven generator disclosed in Japanese Patent Application Laid-open No. 2005-30353, a duct member is disposed around an outer periphery of the engine-driven work machine unit to define a continuous cooling-air passage between the duct member and the outer periphery. A cooling fan is mounted in the cooling-air passage to generate a flow of cooling air from one end of the cooling-air passage to the other end during operation of the engine. A muffler box is connected to the duct member with an inner space communicating with the other end of the cooling-air passage and has an air-discharge port in an upper end. An exhaust muffler of the engine is accommodated in the muffler box, thereby insulating the operational noise of the engine and the work machine and cooling the engine and the work machine as well as the exhaust muffler.
However, in the above-described engine-driven generator, heat from the engine and the exhaust muffler is liable to be confined within the duct member and the muffler box after stoppage of the operation of the engine, leading to a demand for facilitation of natural cooling of the engine and the exhaust muffler.